Borussia Dortmund’s fan department said on Thursday that it had raised concerns about the sponsorship deal with arms manufacturers and technology company Rheinmetall before it was finalised and announced. A statement said that the fan department was informed in a monthly meeting with club leaders and asked for feedback, with the matter to be treated confidential. “In a subsequent open dialogue with representatives of BVB’s management, the fan representatives expressed general concerns about the explosive nature of the partnership and its communication, as well as doubts about its compatibility…